EP 1195877 A1 discloses a power converter system comprising power converter modules connected via a DC link circuit, wherein the DC link circuit comprises two DC voltage busbars and a DC link circuit capacitance arranged between the DC voltage busbars. In this case, each of the power converter modules is assigned a portion of the DC link circuit capacitance, such that each power converter module is assigned an appropriate proportion of the required DC link circuit capacitance (“distributed DC link circuit”), wherein the proportion is at least high enough that it can carry the AC current introduced into the DC link circuit by the module. As a result, a defective power converter module can be decoupled from the common DC link circuit, such that uninterrupted further operation of the other modules at the DC link circuit is possible.
DE 10062075 A1 discloses a converter comprising integrated DC link circuit capacitors, in which conventional DC link circuit capacitors are shared among a plurality of DC link circuit capacitors of relatively small capacitance which may in each case be an integrated part of a half-bridge or bridge module. A converter may consist of a plurality of such half-bridge or full-bridge modules, wherein the capacitances assigned to the individual modules are defined individually on the basis of the electrical properties of the respective modules and a converter comprises at least one module.
WO 2012/162570 A1 discloses a modular system comprising generators and loads coupled to a common DC voltage bus, wherein generators or loads can be removed from the system or added to the system without further changes to the system. In this case, the voltage at the DC voltage bus may fluctuate between a minimum and a maximum operating voltage depending on a present generated power and a presently consumed power, wherein the generated power or the consumed power is controlled depending on the present voltage at the DC voltage bus.
US 2004/125618 discloses a device for converting electrical power which comprises a regulated DC link circuit, to which different sources can be connected in a flexible manner, e.g., DC-DC converters for a photovoltaic generator or for a battery, and sinks, in particular an inverter bridge for feeding electrical power into an AC voltage grid. The DC link circuit may be embodied as part of an inverter of a photovoltaic system or else as part of one of the further DC-DC converters, for example of a battery charging converter. In this case, the electrical power converted by the device must be regulated in such a way that a voltage of the DC link circuit remains within predefined limits.
DE 102006011241 A1 discloses a series of converter devices comprising a multiplicity of converter devices, wherein each converter device has grid and load terminals. A converter device comprises at least one basic converter device, wherein the basic converter devices are electrically connectable in parallel by means of their grid and load terminals, such that converter devices of different power classes are obtainable by the parallel connection of a plurality of basic converter devices using uniform components.